Parkinson's drugs

Question 1

Levodopa (L-DOPA)

Answer 1

• Dopamine precursor: oral, absorbed in small bowel
• Given with carbidopa
• First like for Parkinson’s unless patient is young
• Side effects: hallucinations, dyskinesias, of-on phenomenon, pschosis, N/V, hypotension, dizziness
• MAO-A inhibitors contraindicated (except MAO-B)

Question 2

Carbidopa

Answer 2

• Aromatic amino acid decarboxylase inhibitor
• Inhibits peripheral conversion of L-DOPA to Dopamine, does NOT cross BBB
• Parkinson’s- given with L-DOPA to lower side effects
• Side effects: dyskinesias, on-off phenomenon
• MAO-A inhibitors are contraindicated (except MAO-B)

Question 3

Bromocriptine

Answer 3

• Ergot derivative: D2 agonist, D1 antagonist
• Mild parkinson’s, DA agonism in NMS, hyperprolactinemia
• Side effects: pleural effusions, cough, SOB, pulmonary fibrosis, peripheral DA-like effects, sedation, dizziness
• Titrate slowly due to hypotension

Question 4

Pramipexole

Answer 4

• Non-ergot DA receptor agonist: selective D2 agonist
• Mild parkinson’s (first line), to delay L-DOPA treatment, usually in combo with ropinorole, can use in RLS
• Side effects: more acute, psychosis, mania, nausea, dizziness, sedation, edema, compulsive behavior
• Less effective with motor symptoms of PD

Question 5

Ropinorole

Answer 5

• Non-ergot DA receptor agonist: Selective D2 agonist
• Mild Parkinson’s, restless leg syndrome
• Side effects: more acute, psychosis, mania, nausea, dizziness, sedation, edema, compulsive behavior
• Less effective with motor symptoms of PD

Question 6

Rotigotine

Answer 6

• Non-ergot DA receptor agonist: Selective D2 agonist
• Mild Parkinson’s, restless leg syndrome
• Side effects: more acute, psychosis, mania, nausea, dizziness, sedation, edema, compulsive behavior

Question 7

Apomorphine

Answer 7

• Non-ergot DA receptor agonist
• Rescue therapy for ‘off’ periods (immobility)
• Side effects: more acute, psychosis, mania, nausea, dizziness, sedation, edema, compulsive behavior, peripheral DA effects
• Injectable only, serotonin receptor antagonists contraindicated (eg ondansetron)

Question 8

Entacapone

Answer 8

• COMT inhibitor: prevents breakdown of DA
• Prolongs half life of levodopa, reduces ‘off’ time, primarily works peripherally
• Side effects: dyskinesias, urine dyscoloration, diarrhea, DA side effects
• Short acting: 2 hours

Question 9

Tolcapone

Answer 9

• COMT inhibitor: prevents breakdown of DA
• Prolong half-life of levodopa, reduce ‘off’ time, primarily works peripherally
• Side effects: fatal hepatotoxicity (use only if entacapone fails), dyskinesias, diarrhea, urine dyscoloration, DA side effects
• Short acting: 2 hours

Question 10

Selegiline

Answer 10

• MAO-B inhibitor: prevents breakdown of DA
• Mild early Parkinson’s (monotherapy), may delay onset of l-dopa therapy
• Side effects: hypotension, GI distress, dyskinesia, psychosis, N/V
• Antidote to environmental toxins; at high doses is a MAO-A inhibitor and would have same diet and drug interactions, tyramine crisis, serotonin syndrome, etc. For depression it comes in a patch called EMSAM

Question 11

Rasagiline

Answer 11

• MAO-B Inhibitor: prevents breakdown of DA
• Mild early parkinson’s (monotherapy), may delay onset of l-dopa therapy, adjunct with l-dopa
• Side effects: Hypotension, GI distress, dyskinesia, psychosis, N/V
• Antidote to environmental toxins; at high doses is a MAO-A inhibitor and would have same diet and drug interactions, tyramine crisis, serotonin syndrome, etc. For depression it comes in a patch called EMSAM